Vehicle coolant recycling

ABSTRACT

A process and apparatus for the treatment and recovery of spent vehicle coolant that involves the following steps: 
     a) removing the spent coolant from the engine; 
     b) treating the spent coolant with sodium dimethyldithiocarbamate to cause dissolved metals therein to form insoluble particles; 
     c) treating the spent coolant of step b) with an aqueous basic coagulating agent such as a polyquaternary ammonium compound in its hydroxide form; 
     d) filtering the spent coolant from step c) through a set of filters and then through a bed of carbon particles, to produce a relatively cleaner liquid; and 
     e) adding to the relatively clear liquid a combination of corrosion inhibitors, buffering agents and alkali, whereby the treated coolant can be recycled to the vehicle for effective coolant performance therein.

BRIEF DESCRIPTION OF THE INVENTION

The invention relates to a process for the treatment and recovery ofspent vehicle coolant that involves the following steps:

a) treating spent coolant removed from a vehicle with sodiumdimethyldithiocarbamate to convert dispersed metal containing componentstherein to less dispersed particles;

b) treating the spent coolant of step a) with an aqueous coagulatingagent such as a polyquaternary ammonium compound, in an amountsufficient to aggregate the dispersed metal containing particulates to amore filterable form;

c) filtering the spent coolant through two filters, the first being moreporous than the second, and

d) optionally separating oils, dyes, acidic degradation products, andparticulates from the spent coolant by passing the spent coolant througha bed of carbon particles and/or an open-cell foam;

e) adding to the resultant treated spent coolant a combination ofcorrosion inhibitors, buffering agents and alkali, whereby the treatedcoolant can be recycled to a vehicle for effective coolant performancetherein.

In addition, the invention relates to an apparatus for carrying out thisprocess.

BACKGROUND OF THE INVENTION

The typical internal combustion engine is cooled by providing a coolant(oftentimes called anti-freeze) in cavities that surround the engine. Atypical coolant is an aqueous glycol composition such as aqueousethylene glycol or propylene glycol. These glycols function to reducethe freezing point of coolant and raise the coolant's boiling point,thus assuring that the vehicle's coolant will not freeze or boil over.During operation of the engine, air is constantly drawn into andexpelled from the coolant composition. When the coolant is heated duringengine operation, air is expelled from the coolant. When the engine isat rest and the temperature of the coolant drops, air is absorbed by thecoolant up to the saturation point. This repeated cycle in the life of acoolant provides an oxidation mechanism by which metal ions that aregenerated by corrosive attack of engine surfaces are subjected toinstantaneous oxidation and glycol is thermally oxidized.

Essentially all metal ions when converted to their highest oxidationstate form insoluble hydroxides and oxides in the coolant composition,thus forming a precipitate that collects within the engine's coolantchamber. Some of the metals are oxidized to form precipitated hydroxidesthat deposit on the wall of the coolant chamber and interreact bycondensation reactions to form a beneficial oxide layer. This layerprotects the engine block from serious corrosion. It would beundesirable to have present in the coolant a component that attacks thatbeneficial oxide layer and causes its removal. Such action eventuallyleads to serious corrosion of the engine block. One such component thatwould attack the beneficial coating if present in the coolant indeleterious amounts, is the chloride ion. It will convert the oxidesinto soluble chlorides, thus wiping away the beneficial oxide layer. Forexample, it will convert iron oxides through thermally inducedchlorination, to ferric and ferrous chlorides, and aluminum oxidesthrough thermally induced chlorination, to aluminum chloride. Thesechlorides are very acidic and notorious Friedel-Craft catalysts. Theycan accelerate the decomposition of the coolant and cause corrosion ofmetal surfaces.

Other of the precipitates form within the coolant and serve no usefulfunction. Most of these precipitates are of sufficient size so as todeposit from the coolant to the bottom of the coolant chamber. A minorportion, more like a trace amount, of the precipitates have such a smallsize (more like microscopic in size) that they remain dispersed in thecoolant. Eventually these precipitates have to be removed and thusflushing of the coolant system is an appropriate procedure.

The trace amounts of these metal hydroxides that remain suspendedparticulates within the coolant will, with time, chemically interreactto form dimeric and oligomeric condensates. Such condensates remainsuspended (dispersed) in the coolant. These condensates are difficult toremove by filtration because they have an extremely small particle size.Because the metal atoms in these condensates are at their maximum stateof oxidation, further oxidation of the coolant will not cause thesecondensates to be further oxidized. Nor will further oxidation causethese condensates to drop out of dispersion in the coolant.

As noted above, some of the coolant becomes chemically altered. Forexample, a minor portion of the ethylene glycol is periodicallythermally oxidatively attacked to form a number of decompositionproducts such as glycolic acid, formic acid and oxalic acid. These acidsper se do not cause the coolant to become acidic, that is, cause thecoolant to have a pH below about 7. As pointed out in an article byCooper, Hannigan and McCourt, "A One Thousand Car Assessment of the U.S.Car Population Cooling Systems," SAE Technical Paper Series, Proceedingsof the 2nd Automotive Corrosion Prevention Conference, AutomotiveCorrosion and Prevention Conference, Dearborn, Mich., December 5-7,1983, the mean pH of the ethylene glycol coolant in the car populationis 8.7, with only 2.3 percent of the cars having coolant with a pH of 7or less. Since the pH of the coolant is dictated by the buffer system inthe coolant, the coolant will generally possess a substantial alkalimetal ion content. This causes the acids to compete with the acidiccomponent of the buffer for the alkali metal ions. These decompositionproducts, as salts and free acids, remain as soluble components of thecoolant. Because they are acids, their accumulation in the coolantreduces the coolant's pH. With reduction of pH comes increased corrosionof engine surfaces resulting in increased concentrations of metalhydroxide and oxide precipitates. Eventually, the coolant becomes sofouled by this decomposition that it must be either replaced orreconditioned.

Conley, J. H. and Jamison, R. G., "Reclaiming Used Antifreeze," MERADCOMReport 2168, U.S. Army MERADCOM, Fort Belvoir, Va., March 1976, describean early effort by the U.S. Army in treating recycled vehicle coolant.As these authors note, coolants are repeatedly subjected to oxygenation.Such oxygenation is the cause for thermal oxidative degradation of thecoolant. The authors recommend discarding coolant with a freeze pointabove 5° F., which means that the coolant is too degraded for furthertreatment. A coolant with such a high freeze point would have a low pHbecause of thermal oxidation of the ethylene glycol. The authorsproposed two methods. Method I involves--

1. Take freeze point of coolant. If above +5° F., discard; do not retainfor processing.

2. Place antifreeze drained from vehicles into holding tank.

3. Allow antifreeze to settle for several hours or until fairly clear.The longer the settling time, the more solids will have settled and lesswill remain to be filtered.

4. Filter through a cloth filter.

5. Pass filtrate through cationic resin (IR-120 or equivalent).

6. Pass effluent through activated carbon.

7. Pass effluent through calcium carbonate (marble).

8. Add inhibitor which involves bringing the antifreeze to its normalrange of reserve alkalinity and pH with Federal Specification 0-I-490corrosion inhibitor. Check freeze point, adding new antifreeze or waterto obtain desired freeze point.

9. Flush vehicle cooling system with water and recharge.

Method II proposed by the authors involves

1. Take freeze point of coolant. If above +5° F., discard; do not retainfor processing.

2. Drain cooling system, and filter the antifreeze through cottonbatting or cloth filter to remove rust and solids.

3. Add Inhibitor A at the rate of 3 percent, or 1 pint per 16 quartscoolant.

4. Flush cooling system with water until the water is clear.

5. Replace the inhibited, used antifreeze solution.

Method I described by Conley and Jamison above, with the exception ofthe use of cation exchange resin, activated carbon and calciumcarbonate, was employed with minor differences by PECO (formerlyPhiladelphia Electric Co., Philadelphia, Pa.) in 1987 to successfullyreclaim antifreeze.

There are described in the literature a variety of systems directed tothe treatment of spent engine coolant that allows for the recovery andrefurbishing of such coolant. Illustrative of such technology are aseries of patents to the Wynn Oil Company, such as U.S. Pat. Nos.4,083,393, 4,091,865, 4,109,703, 4,178,134, 4,209,063, 4,293,031,4,791,890, 4,793,403, 4,809,769, 4,899,807, 4,901,786, 5,201,152,5,078,866, 5,306,430, 5,318,700, and Re. 31,274. For example, Filowitz,et al., U.S. Pat. Nos. 5,021,152 and 5,078,866 relate to the treatmentof coolant with agents that precipitate anions and cations and theremoval of such precipitants. The patents describe the addition of"Composition A" and "Composition B" to the recycled coolant. Accordingto the patents, "A" precipitates anions, i.e., the negatively chargedion, especially the ion that migrates to an anode in electrolysis, suchas sulfate, chloride, etc. "B" precipitates cations, such as metalions--i.e. of lead, iron, copper, etc. According to the patents,Composition A is a material called "Protazyme," which is defined as an8% aqueous solution of cationic polyelectrolyte HYDROFLOC 865 having thechemical formula ##STR1## where X is undefined. The patents confuse thedescription of Composition B. Composition B, called "NETAMOX," is "a 5%aqueous solution of anionic polyelectrolyte, or equivalent, and a 5%aqueous solution of heavy metal precipitant" that appear to be "Sodiumdimethyl dithiocarbamate in 0.5% to 1.5% aqueous solution form" and"HYROFLOC 495L" that possesses the chemical formula ##STR2## where X isundefined. In chemistry, the "X" group is frequently used to denotehalogen.

It should be noted that the formula of HYDROFLOC 865 and 495L is thesame for materials possessing entirely different properties. IfComposition B is 5% of the anionic polyelectrolyte and 5% of the DTCsolution, what is the rest of the composition? That is not explained inthe patents.

In both patents, a filtered coolant is treated by the addition ofchemical agents such as corrosion inhibitors, pH adjustment chemicalsand fresh coolant, such as ethylene glycol or propylene glycol,depending upon the base of the spent coolant being treated.

PCT/US92/00555 and U.S. Pat. No. 4,946,595, to Miller, describe aprocess for the treatment of a spent coolant outside of the engine. Thetreatment involves an oxidation step, which, as noted above, will haveno impact on the character and properties of the spent coolant. Anotherstep utilized by Miller is the treatment of the spent coolant with analkali such as sodium hydroxide, to not only raise the pH, but to alsoform salts of the coolant decomposition products, such as glycolic acid,formic acid and oxalic acid. According to Miller, these saltsprecipitate from the coolant. Interestingly, Miller also describesadding such salts to the coolant to create a common ion effect. In thelatter case, Miller is suggesting that the so-called salts thatprecipitate are soluble in the coolant, clearly indicating that saltformation does not result in acid removal by precipitation. The nextstep in the process is to pass the coolant through a series of filters,the first filter effecting a coarse separation, and the second filtereffecting a finer separation. An optional treatment is to pass thetreated coolant through an ion exchange resin to remove alkaline earthmetal ions. However, at the pH of the coolant at that step of theprocess, all such alkaline earth metal ions are fully oxidized to theirhydroxides which are insoluble in the coolant. All but a trace amount ofthese hydroxides would have already precipitated from the coolant.

The PCT application describes a variety of additive packages for spentcoolant. For example, the PCT application (at page 15) describes the useof sodium dimethyldithiocarbamate as part of an inhibitor package in thefollowing terms:

"An additional precipitating agent which may be added to the additivecomprises a sodium salt of the class [sic] carbamates to removedissolved metals from the coolant solution for retention in thefiltration means. Preferred sodium carbamates include sodium dimethyl ordiethyl dithiocarbamate or sodium trithiocarbamate [sic] present in theadditive in an amount of about 0.5%."

At page 20, in Table F of the PCT application, Miller describes achemical additive package that contains sodium dimethyl or diethyldithiocarbamate. The following table embellishes on the formulationdescribed in Table F by functionally describing the components wheresuch makes sense to do:

                                      TABLE F                                     __________________________________________________________________________    Page 20, PCT/US92/00555                                                       __________________________________________________________________________    (a) About 2.0 percent sodium nitrate. Known aluminum corrosion inhibitor      (b) About 1.5 percent ACCUMER 3000. Rohm & Haas Acrylate copolymer;           solids disper-                                                                sant                                                                          (c) About 1.5 percent BELCLENE 201. Aqueous solution of poly(maleic           acid)                                                                         [homopolymer of 2-butenedioic acid], now sold by FMC Corporation, Process     Additive Di-                                                                  vision, 1735 Market St., Philadelphia, PA 19103                               (d) About 1.5 percent sodium molybdate decahydrate.Na.sub.2 MoO.sub.4.2H.s    ub.2 O-- very effective                                                       corrosion inhibitor, expensive                                                (e) About 0.75 percent sodium nitrite. Corrosion inhibitor for iron. Not      used in passenger                                                             vehicles. Can form carcinogenic nitrosamines when mixed with amines. Used     in heavy                                                                      duty coolants for diesel engines with wet sleeve cylinders.                   (f) About 2.0 percent sodium tolyltriazole 50% solution. Tolyltriazole, a     primary copper                                                                and brass corrosion inhibitor                                                  ##STR3##                                                                     (g) About 0.5 percent dimethyl or diethyl dithiocarbamate. Inhibitor or       precipitating                                                                 agents for metals.                                                            (h) About 1.5 percent sodium hydroxide. NaOH, used to raise pH of             coolant.                                                                      (i) About 0.1 percent dimethyl silicone. A defoamer; general structure:        ##STR4##                                                                     (j) About 0.5 percent polyalkylene glycol. Number of these polymers are       used as anti-                                                                 foam, e.g., PPG 2025 and 50HB-5100 sold by Union Carbide Chemicals &          Plastics Co.,                                                                 Inc.                                                                          (k) About 1.0 percent Philadelphia Quartz N solution. Sodium silicate         solution, very                                                                effective aluminum corrosion inhibitor.                                       (l) About 0.5 percent Dow Corning Q1-6083. A silicone phosphonate used to     stabilize                                                                     silicates in concentrated coolant solutions or in the additive package.       (m) About 85.15 percent softened water.                                       __________________________________________________________________________

A system that was commercialized in the past was sold by ECP, Inc.,Westchester, Ill. It involved the vacuum removal of spent coolant froman engine, subjecting the coolant to filtration, and the addition of a"Coolant System Protector" to the filtered spent coolant.

Woyciesjes et al., U.S. Pat. No. 5,223,144, describe a process fortreating an aqueous spent coolant composition by adjusting its pH to theacid range, e.g., 4.0-7.5, by adding an acid, and then adding acid saltsto effect precipitation of heavy metal impurities in salt or complexform from the spent coolant. Also included in the process description isthe treatment of the acidic coolant composition with coagulating andflocculating agents, filtration of the acidic coolant, passing theacidic coolant through an activated carbon bed, through a distillationstep, and a skimming step to remove precipitates.

SUMMARY OF THE INVENTION

This invention relates to a process and apparatus for the treatment of aspent alkaline and glycol-based coolant removed from an internalcombustion engine that avoids the significant introduction of chlorideand other acidic anions that can attack metal and metal oxide surfacesin the engine's coolant chamber when the coolant is reintroduced to theengine's coolant chamber. In addition, the process of the inventionutilizes systems that actually reduce trace oxidized metal precipitatesdispersed in the coolant and oxidative decomposition products of thecoolant. The process of this invention accomplishes this withoutacidifying the coolant.

The invention relates to a process for the treatment and recovery ofsuch spent alkaline and glycol-based coolant that involves the followingsteps:

a) removing the spent alkaline coolant from the engine;

b) treating the spent alkaline coolant in separate steps with thefollowing treating chemicals:

i) adding sodium dialkyldithiocarbamate--to cause dispersed metalcontaining components therein to form larger and better definableinsoluble particles; and

ii) subsequently and separately adding a basic coagulating agent such asa basic polyquaternary ammonium compound to agglomerate the particlesinto a filterable form;

c) filtering the spent coolant through at least two filters, the firstbeing more porous than the second, to obtain a relatively clear liquid;and

d) optionally separating oils, dyes, acidic degradation products, andparticulates from the spent coolant by passing the spent coolant througha bed of carbon particles and/or an open-cell foam;

e) adding to the relatively clear liquid a combination of corrosioninhibitors, buffering agents and alkali, whereby the treated coolant hasa pH between about 8 and about 11, and can be recycled to the engine foreffective coolant performance therein.

The invention relates as well to an apparatus for the treatment of suchspent coolant. The apparatus involves a recycler that effects on-carrecycling of the spent alkaline coolant or bulk recycling of the spentalkaline coolant. The bulk recycler circulates through a pump, coolantcollected from a number of vehicles, into a tank, then through theaddition of the chemical treating additives, the filters and carbon bedand back into the tank. Put into the coolant in monitored steps are thetreatment chemicals comprising sodium dialkyldithiocarbamate to causedispersed metal containing components therein to form larger and betterdefinable insoluble particles and a basic coagulating agent such as abasic polyquaternary ammonium compound to agglomerate the particles intoa filterable form. This bulk recycling is repeated until the cleanup ofthe coolant is completed. Aliquot parts of the coolant collected in thetank, after cleanup and chemically refurbished with inhibitor, bufferand pH adjustment, may be used in a vehicle. In the case of on-carrecycling, the coolant is circulated through the function of a pump outof the vehicle through a heater Tee, through the filters and carbon bed,then back to the vehicle through a heater hose fitting. In thesesystems, the chemical treatment and chemical refurbishing of the coolantare effected by independently aspirating the treatment additives and therefurbishing chemicals to the coolant so that the treatment additivesand the refurbishing chemicals are essentially uniformly distributed inthe coolant undergoing treatment. In both systems, the apparatus of theinvention involves

a) a pump with a pressure side and a vacuum side, a holding tank, areceptacle for treatment and refurbishing chemicals with a controlledopen connection to the vacuum side of the pump, air inlets for the pump,a cannister containing a bed of carbon particle, and one or morecartridge filters, desirably a first filter cartridge for removingcoarse particle, and a second filter cartidge for removing finerparticulates;

b) in the case of the portable unit, a connecting line from a Teeconnector in a heater hose of the cooling system of an internalcombustion engine, providing fluid connection to one side of the pump;

c) in the case of the portable unit, a connecting line from the radiatorof the cooling system of the internal combustion engine providing fluidconnection to the other side of the pump;

d) in the case of both units, linkage of one or more of the connectinglines to the holding tank, and then to one or more sides of the pump;

e) in the case of both units, an aspirating control valve that controlsopen connection between the receptacle and the vacuum side of the pump;

f) in the case of both units, location of the filter cartridges andcarbon bed cannister in indirect connection in series and in fluidconnection with one or more sides of the pump whereby fluid can betransported through the cartridges and cannister in a step-wise manner.

In carrying out the process, a first step is to convert the dispersedcondensed metal hydroxides into larger and better definable insolubleparticles that can be removed from the spent coolant. This isaccomplished by treating the spent coolant with sodiumdialkyldithiocarbamate, their homologs, and equivalent reducing agents.The alkyl may be lower alkyl, such as alkyl that contain 1 to about 4carbon atoms. The preferred alkyl is methyl. Sodiumdimethyldithiocarbamate is frequently characterized in the literature as"DTC" or "SDDC" (Hawley's Condensed Chemical Dictionary, 12th Edition,Van Nostrand Reinhold Company, New York, N.Y.). The resultant coolantcontains additional particulate matter, as well as byproducts of anydecomposition of sodium dimethyldithiocarbamate. These particulates andthe byproducts should be removed from the coolant before it is recycled.There are three steps in the process that assures removal of particulatematters. The filtration step uses a series of large and small porediameter filters to remove substantially all of the particulate matterpresent in the spent coolant. The carbon bed treatment reduces theaforementioned decomposition products, such as the organic acids andSDDC decomposition products.

On treating the spent alkaline coolant with SDDC, the coolant is treatedwith an aqueous basic coagulant. The coagulant is any material that whenadded to the spent coolant neutralizes charges of particles in colloidalsuspension, and allows these particles to aggregate into filterableparticles. The particles in colloidal suspension include insoluble metalcontaining components and other dispersed materials such as phosphatesand sulfates. The coagulant is either soluble or dispersible in water,exhibits a pH greater than 7, and can be added to the spent coolant froman aqueous medium.

The spent coolant flushed from the cooling system contains a variety ofdifferent sized particles, especially after treatment with SDDC and thebasic coagulant. It has been experienced in treating such spent coolantthat a multi-filtering system is preferable. The first step in removingparticulate matters is to separate the large particles from the spentcoolant. This is accomplished by passing the spent coolant through acoarse filter, that is, a filter with relatively large pores. Theresultant spent coolant can then be passed through a fine filter, thatis, a filter with relatively small pores, so as to remove the smallparticulates present in the coolant. This sequential filtering treatmentminimizes plugging of the filters and extends the life of the processcycle.

The above process, in attempting to reduce dispersed metal content,introduces a variety of chemical decomposition products to a coolantthat is already loaded with oils, dyes and acidic decomposition productsof the glycols. It has been determined that a most effective procedurefor at least partially removing these contaminants is to pass the spentcoolant through a carbon bed. The bed may be made of carbon particlesthat are either unactivated or activated, with the activated carbonparticles being preferred. A particularly preferred embodiment of theinvention is the use of monolithic carbon particulate filters in whichthe carbon particles are interbonded to provide a single porousstructure through which the coolant undergoing treatment is passed.

The spent coolant has now been subjected to sufficient removal ofdispersed and bulk precipitated metal containing components, as well asthe various decomposition products. This replenished coolant does notpossess the necessary corrosion inhibitive additives and the appropriatepH for subsequent desired utilization in an internal combustion engine.This is accomplished by adding to the treated coolant the necessarycorrosion inhibitors and pH adjustment chemicals.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic view of the apparatus of the invention (i.e., thecoolant recycler) for carrying out the process of the invention.

FIG. 2 is a view of the coolant recycler of FIG. 1 and schematicallyillustrating a separate aspirator receptacle and connection to thevacuum side of the pump.

FIG. 2A is schematic view of an aspirating basin serving as part of thedelivery system for treatment chemicals and additives in the coolantrecycler for the coolant undergoing treatment.

FIG. 3 illustrates a variety of fluid flow patterns in the schematicview of FIG. 1 that are used or useful in practicing the method andcoolant recycler of the invention.

FIG. 4 is a schematic view of an internal combustion engine showing theconnection sites for the lines from the coolant recycler of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

While others have suggested using sodium dimethyldithiocarbamate inspent coolant compositions to precipitate soluble metals, it is a knowninhibitor, and therefore, its actual function when added in conjunctionwith other inhibitors, can relate more to inhibition than oxidized metalcomplexation that leads to greater precipitation of metal containingcomponents. The small amounts of dispersed oxidized metal present in aspent coolant taken from an internal combustion engine may result fromOstwald's ripening of condensed metal hydroxides along the lines of thefollowing reactions: ##STR5## to form colloidal particles, dimeric oroligomeric, that defy separation by conventional filtration. SDDC, whichhas the formula ##STR6## has the capacity of complexing these dispersedparticulates into large enough particles that, precipitate from thecoolant and thus can be filtered by a more porous conventional filter.The size of the particles are still small, and therefore, the particlesare removed by a fine filter, and to some extent, in a large filteraided by the presence of larger particulate aggregates. The amount ofSDDC, or its equivalent, that is added to the spent coolant undergoingtreatment ranges from about 0.01 to about 10 weight percent, basis theweight of the coolant, preferably from about 0.05 to about 7 weightpercent, same basis, and most preferably from about 0.1 to about 5.5weight percent, same basis.

In a separate step, the spent coolant that has been treated with SDDC isthen treated with an aqueous basic coagulant, The coagulant is anymaterial that when added to the spent coolant neutralizes charges ofparticles in colloidal suspension, and allows these particles toaggregate into filterable particles. The particles in colloidalsuspension include insoluble metals and other dispersibles such asphosphates and sulfates. The coagulant is either soluble or dispersiblein water, exhibits a pH greater than 7, and can be added to the spentcoolant from an aqueous medium.

The preferred coagulant is a basic polymer. In particular, the basicpolymer contains quaternary ammonium hydroxide moieties either in thepolymer backbone or on groups pendant from the polymer backbone. Wherethe quaternary ammonium hydroxide moieties are in the backbone, thepolymer is a condensation polymer, and when the quaternary ammoniumhydroxide moieties are pendant from the backbone, the polymer is anaddition polymer. In essentially all cases, the basic polymer is derivedfrom an acidic polymer that is formed by reaction of a monomer thatcontain a tertiary amine strong acid salt moiety. After formation, theacidic polymer typically exhibits a pH below 4 in aqueous solution. Theacid polymer is treated to make it basic. The treatment involvesreplacing the strong acid moiety with hydroxyl ions. After treatment toreplace strong acid ions with hydroxyl ions, the polymer issubstantially basic, exhibiting a pH of greater than 7, preferablygreater than 8. and typically greater than 9. In the usual case, thepolymer's pH is not greater than about 12.

A basic polymer may be a condensation polymer derived from the reactionof ethylene dichloride and ammonia, ethylene dichloride, ammonia, andethylenediamine and other polyamines. The acidic polymer thus formed issubjected to ⁻⁻ OH substituted anion exchange resin treatment or analkali metal hydroxide (such as sodium hydroxide, potassium hydroxide,lithium hydroxide, rubidium hydroxide and cesium hydroxide) tosubstitute ⁻⁻ OH ions for the choride ions present on the polymerbackbone, and form a basic polymer. In the alkali meted hydroxidetreatment, the alkali metal chloride can be separated from the polymerby solvent extraction. The condensation polymer is preferably derived byreacting epichlorohydrin (EPI) and dimethylamine (DMA), either in thepresence or absence of any cross-linking agents, to form either linearEPI-DMA polymers or to form branched and/or cross-linked EPI/DMApolymers. These branched and cross-linked EPI-DMA polymers may beobtained by reacting epichlorohydrin and dimethylamine in the presenceof prescribed amounts of any cross linking agent chosen from the groupconsisting of ammonia, ethylene diamine, hexamethylenediamine,diethylene triamine, triethylene tetraamine, and mixtures thereof.Subsequent treatment of a ˜10 weight % aqueous polymer solution with an⁻⁻ OH substituted anion exchange resin or alkali metal hydroxide, willmake the polymer basic. Illustrative ⁻⁻ OH substituted ion exchangeresins are Amberlyst A27 and Amberlite IRA 402, both sold by Rohm & HaasCompany, Philadelphia, Pa.

A preferred basic polymer is a polymer having a weight average molecularweight ranging from about 1,000 to about 50,000 and is a linear EPI-DMApolymer or a mixture of polymers which contains linear polymers ofepichlorohydrin and dimethylamine that have been subjected to theaforesaid ion exchange resin or alkali metal hydroxide treatment. Theselinear EPI-DMA polymers are obtained by reacting epichlorohydrin and DMAin a mole ratio ranging from about 0.95:1.0 to about 1.05:1.0. Thepolymers may also contain either branched and cross-linked EPI-DMApolymers. The polymers are cross-linked or branched by adding variouscrosslinking/branching agents such as ammonia, ethylene diamine,hexamethylene diamine, diethylene triamine, triethylene tetraamine, andmixtures thereof, where the cross-linking/branching agent is presentfrom about 0.05 to about 10.0 weight percent of the polymer. Preferably,the cross linking agent is present at from about 0.1 to about 2.0 weightpercent of total polymer weight. Again, after formation, the polymer isacidic, typically exhibiting a pH below 4 in aqueous solution. Aftertreatment to replace halogen ions with hydroxyl ions, the polymer issignificantly basic, as indicated above.

The preferred polymer is an EPI-DMA polymer which is essentially linearin nature and formed by the reaction of epichlorohydrin anddimethylamine, at the appropriate mole ratios stated above, with theoption of a small amount of crosslinking agent such as ethylene diamine.Other suitable condensation polymers are the polymers obtained byreacting essentially molar equivalent amounts of ethylenedichloride andammonium or ethylenedichloride and ammonia with varying molar amounts ofmethyl chloride to form a quaternary condensation polymer. The preferredethylene dichloride ammonia polymer is a polymer that contains ethylenedichloride and ammonia in molar ratios ranging from about 0.95:1 toabout 1.05:1 wherein the amine nitrogens in the polymer have beenquaternized by reacting with methyl chloride, dimethylsulfate, or otherquaternizing agents, such that at least 10 mole percent of the aminonitrogen contained in the condensate polymer backbone has beenquaternized. Again the weight average molecular weight for any of thesecondensation polymers ranges (all molecular weights described herein areweight average molecular weights) between about 2,000 to about 75,000.The preferred molecular weight is from about 2,500 to about 50,000 andthe most preferred molecular weight is from 3,000 to about 30,000. Ofcourse, such polymers are subjected to ion exchange resin or alkalimetal hydroxide treatment, to render them basic.

Another basic polymer is an addition polymer of diallyl dimethylammonium chloride, (hereafter DADMAC) or equivalent salts thereofsubsequently treated to convert the polymer to the ⁻⁻ OH basic form.This DADMAC containing polymer preferably ranges in average molecularweight between about 50,000 and about 150,000 and contains at least 50mole percent of the DADMAC monomer, preferably at least 80 mole percentDADMAC, and most preferably the polymer is a homopolymer of DADMAC.These polymers too are subjected to ion exchange resin or alkali metalhydroxide treatment, to render them basic.

Although not as efficient as the condensate polymers, the DADMAC vinylicpolymers can also be effectively used in the practice of the invention.These DADMAC polymers preferably contain at least 80 mole percentdiallyldimethyl ammonium chloride, or an equivalent salt thereof, andmost preferably contain 100 mole percent diallyldimethyl ammoniumchloride, that is a homopolymer of DADMAC. Treatment with the ionexchange resin or alkali metal hydroxide, converts the chloride tohydroxide. These homopolymers have a weight average molecular weightranging from about 25,000 to about 150,000 with the preferred molecularweight ranging from about 50,000 to about 150,000.

Another basic polymer useful in the practice of this invention is a highmolecular weight basic emulsion polymer. This polymer generally comprisean acrylamide copolymer produced with a variety of comonomers; e.g.,ethylenically unsaturated monomers. The monomers can be either aminecontaining monomers or quaternary ammonium salt containing monomers asdepicted by the following formulas: ##STR7## wherein R₁ in the aboveformula represents hydrogen or lower alkyl (e.g., C₁ -C₄); R₂ and R₃independently represent hydrogen or hydroxyl; R₄, R₅, and R₆independently represent lower alkyl (e.g., C₁ -C₄) or benzyl; Arepresents O or NH, y is 1-5; and X represents chloride or methosulfate.Subsequent treatment of the polymer with ⁻⁻ OH substituted anionexchange resin treatment or an alkali metal hydroxide, as aforesaid,converts X to ⁻⁻ OH.

Typical of the monomers commonly copolymerized with acrylamide are: theaminoalkylacrylate esters and their quaternary ammonium salts(quaternization with such quaternizing agents as methyl chloride,dimethyl sulfate, benzyl chloride and the like); theaminoalkylmethacrylate esters and their corresponding quaternaryammonium salts; the aminoalkylacrylamides and their correspondingquaternary ammonium salts; the aminoalkylmethacrylamides and theircorresponding quaternary ammonium salts; the diallyldialkylammonium saltmonomers; the vinylbenzyltrialkylammonium salts; and the like.Non-limiting examples of the monomers that can be used to prepare thepolymers are: diallyldimethylammonium chloride; diallyldiethylammoniumchloride; acryloyloxyethyltrimethylammonium chloride,methacryloyloxyethyltrimethylammonium chloride;acryloyloxyethyltrimethylammonium methosulphate,methacryloyloxyethyltrimethylammonium methosulphate;acryloyloxyethyldiethylmethylammonium chloride;methacryloyloxyethyldiethylmethylammonium chloride;methacryloyloxyethyldiethylmethylammonium chloride; and,methacryloyloxyethyldiethymethhylammonium chloride. Mixtures of thebasic monomers together with acrylamide to prepare the polymers are alsouseful. Also contemplated are homopolymers of the monomers, as well ascopolymerization of mixtures of monomers without acrylamide. The abovedescription of useful monomers in no way limits the practice of theinvention. Those skilled in the art will be familiar with other monomerswhich can be used to prepare the basic, high molecular weight polymersuseful in the invention. Those skilled in the art will recognize thatthe acid nature of the resulting polymer will be changed to a basicnature by treatment of the polymer with ⁻⁻ OH substituted anion exchangeresin treatment or an alkali metal hydroxide, as aforesaid, whichconverts X groups (e.g., chloride or methosulfate) to ⁻⁻ OH.

The basic polymers can have a wide range of charge densities, from justa few mole percent of basic monomer up to 100 mole percent of basicmonomer (homopolymers) in which each repeating mer contains a bonded ⁻⁻OH. The molecular weights of the basic polymers are not critical to theinvention, but can range from a few thousand to several million

Preparation of a basic emulsion polymers is well known and is describedin the literature in detail. Typical procedures and methods can befound, for example, in reissued U.S. Pat. No. 3,624,019, reissued as Re.28,474.

Descriptions of suitable polymers that can be converted to basicpolymers containing ⁻⁻ OH groups, as described herein, can be found inthe article on "Polyamines and Polyquaternary Ammonium Salts", in theEncyclopedia of Polymer Science and Engineering, Second Edition, JohnWiley & Sons, New York, Volume 11, pages 489-507. It is to be understoodthat the invention is in no way limited to the above descriptions ofbasic polymers. Those skilled in the art will recognize other basicpolymers that will be useful in the practice of this invention. Mixturesof basic aqueous polymers are also contemplated by this invention.

Illustrative of desirable polymers, which after hydroxylization areconverted to basic polymers, are the following:

1. Commercial basic copolymer of acrylamide andacryloyloxyethyldiethylmethylammonium chloride, containing about 8 mole% of the basic monomer, having a molecular weight in excess of onemillion.

2. Commercial basic copolymer of acrylamide andacryloyloxyethyldiethylmethylammonium chloride, containing about 40 mole% of the basic monomer, having a molecular weight in excess of onemillion.

3. Commercial basic copolymer of acrylamide andmethacryloyloxyethyldiethylmethylammonium chloride, containing about 7.5mole % of the basic monomer, having a molecular weight in excess of onemillion.

4. Commercial basic copolymer of dimethylamine and epichlorohydrin,having a molecular weight of about 10,000, in 40% aqueous solution.

5. Commercial basic diallyldimethylammonium chloride polymer, having amolecular weight of about 500,000, in 18% aqueous solution.

Conversion of acid substituted amine polymer can be carried out bymixing particles of the ion exchange resin, such as Amberlyst A27 andAmberlite IRA 402, with the acid substituted amine polymer, in an amountsufficient to essentially remove all of the acid moieties from thepolymer. Preferably, the amount of ion exchange resin is sufficient toconvert an otherwise acidic polymer to a basic polymer that exhibits analkaline pH in water, as aforesaid. A preferred procedure involvesflowing an aqueous solution or dispersion of the acidic polymer througha bed of the ion exchange resin, and repeating the procedure, ifnecessary, until the polymer exhibits the desired degree of basicity.Conversion of the acidic polymer with alkali metal hydroxide can becarried out in an aqueous medium, including the presence of an organicsolvent to assure dissolution of the polymer, using at least astoichiometric amount of the alkali metal hydroxide to the amount ofacidic moities present in the polymer. The alkali metal salts can beremoved from admixture with the ⁻⁻ OH containing quaternary ammoniumpolymer by extraction using a mixture of solvents possessing differentdegrees of solubility for the salt and the ⁻⁻ OH containing polymer. Thedegree of conversion of these acidic groups to ⁻⁻ OH can be measured bythe basicity of the resultant polymer.

The amount of basic polymer used in the practice of the process of theinvention is not narrowly critical and is typically dependent upon theamount of solids generated by the treatment of the spent coolant withSDDC or its equivalent. The higher the solids content of the spentcoolant that is generated by SDDC, or its equivalent, the greater willbe the amount of basic polymer employed. In general, the amount of basicpolymer that is employed will range from about 0.01 to about 10 weightpercent of the weight of the spent coolant, preferably from about 0.05to about 8 weight percent, same basis, and most preferably, form about 1to about 6 weight percent, same basis.

The basic polymer and SDDC may be combined and added together, in orderto treat the spent coolant, as stated above. However, it is preferred toseparately treat the spent coolant with SDDC and the basic polymer tominimize premature reaction between SDDC and the basic polymer.

The next step in the process is the treatment of the spent alkalinecoolant by passing it through the filters or a fixed bed of particulatecarbon particles. Preferably, the carbon particles are made of activatedcarbon. The fixed bed of carbon particles is assembled in a canister orcartridge form to allow its convenient arrangement in the apparatus. Thecarbon particles may be held together by a netting material such as onemade of nylon, polypropylene, polyester, and the like materials. Thenetting materials may be woven, knitted or nonwoven (e.g., spunbonded)fabric constructions. An advantage of the netting is that it can performpre-filtration of the coolant being passed through the carbon bed. Wherethe netting material effects such a result is when the pores of thenetting are sufficiently small enough to block particulates in thecoolant from passing through the netting into the bed. Preferably, suchnettings have a pore size of about 1 to 100 microns, preferably fromabout 5 to about 50 microns. A particularly desirable netting is aspunbonded polypropylene fabric, in which the fibers deposited in thefabric have a randon laydown and are either fused together and/oradhesively bonded. Such fabrics are commercially available from a numberof sources. One may also hold the carbon particles by partiallyencapsulating them with a thermosetting resin material such as an epoxy,phenol formaldehyde, polyamide, polyesters, and the like type resins ora thermoplastic resin such as adhesive forms of polyvinyl acetate,polyethylene vinylacetate copolymers, nylons, linear polyesters,polyarylethers, polyethersulfones, polysulfones, polyarylimides,polystyrene, polymaleic acid, polyacrylates, polyacrylic acids,polymethacrylic acids, and copolymers of the foregoing. The partiallyencapsulation of the particles is a desirable method for makingmonolithic bonded carbon particulate beds. In the case of partiallyencapsulated particles and particles held together by netting, the bedof carbon particles are shaped so that they conveniently fit within acanister or cartridge housing, typically a cylindrical one. Manydifferent bed arrangements are feasible in carrying out the process. Thebed arrangement may simply occupy a section of the canister or cartridgehousing and the spent coolant passes directly through it to an exit inthe housing. The bed may be designed to be shaped as a cylinder with acore opening in the central axis of the cylinder. In that case, thespent coolant will flow in a radial manner from the outside through thecylindrical bed and be captured within the open core of the bed andallowed to flow to an opening in the housing. The preferred flow isradically into the center hollow core of the bed, however the radialflow may be reversed from the open internal core of the bed to theoutside circumference of the bed. The purpose of this step is to reducethe presence of oils that coolants typically pick up during an internalcombustion engine's operation, reduce the variety of byproduct organicsthat the recycled coolant contains, and reduce the amount of organicacids present in the spent coolant. The carbon bed removes combinationsof organic acids, some of the coagulant and some oil present in thecoolant by adsorption. It also removes some of the dye in the coolant.

Activated carbon is an amorphous form of carbon characterized by highadsorptivity for many gases, vapors, and colloidal solids. The carbon isobtained by the destructive distillation of wood, nut shells, animalbones, or other carbonaceous material. It is "activated" by heating to800°-900° C. with steam or carbon dioxide, which results in a porousinternal structure (honeycomb-like). The internal surface area ofactivated carbon averages approximately 10,000 square feet per gram.

The amounts of these impurities that are removed from the spent coolantis dependent upon the residence time of the spent coolant in the fixedcarbon bed. If maximum removal is desired, then, of course, an extendedresidence time in the carbon bed is necessary. The residence time can becontrolled by the rate of flow of the spent coolant through the carbonbed, or the number of passes that the same spent coolant makes through acarbon bed, or by increasing the number of carbon beds in order toassure maximum residence time. When the concentration of impurities thatcan be removed by the bed is not reduced to a desired level at a fixedand standard rate of flow of the spent coolant in the bed, then itbecomes apparent that the bed should be replenished by a new bed ofcarbon particles. Turnover of carbon particle beds is dependent upon theprocessing objectives of the process user.

A particularly preferred form of the carbon particulate bed is themonolithic bonded carbon particulate bed. A form of such type of bed inan extruded activated carbon filter. They typically comprise virginactivated carbon powder, a thermoplastic binder and, optionally,specialty adsorbents such as zeolites or oxidizing filtration media,manufactured as continuous lengths of rod, tube, sheet, slab, or asother complex shapes. The resulting products are highly porous andextremely uniform, providing high-performance adsorption and particulatereduction at low flow resistance when fabricated into finished filterelements. Extruded activated carbon filters are manufactured asthick-walled, hollow cylinders in a variety of different outside andinside diameters and in lengths from 0.100 (wafer) to 60 inches. Thefilters can incorporate a wide variety of prefiltration structures andend cappings. These filters are typically fitted with a protectiveprefiltration medium and encapsulated around their edge using aself-gasketing structural foam frame. Generally, an extrusion can beproduced using carbon powder, granules or pellets, with particle sizesranging from about 10 to 5,000 μm. Specialized adsorbent additives canbe coated onto the individual carbon particles and then extruded toproduce complex composites with unique adsorptive properties.Performance advantages for these extruded activated carbon filtersinclude:

They minimize the release activated carbon particles during startup oroperation as compared to some granule activated carbon filter (not ofthe extruded type), in which the granules are unbonded, that willrelease carbon fines even after the filter elements have been in servicefor an extended period of time.

They do not channel, bypass, or fluidize because extruded carbon is arigid structure that prevents movement of the adsorbent particles orformation of channels and defects in the adsorbent structure. On theother hand, granulated activated carbon filters consist of loose beds ofparticles that are often loosely packed into a nonrigid plastic tube;therefore, bypass of the carbon is common because the plastic containeroften expands away from the carbon when under pressure, leaving asorbent-free zone. Under sufficient flow, the entire bed will fluidizeand the integrity of the adsorbent bed can be lost. This necessitatescareful use of such granulated activated carbon filters.

Coolant flows through these extruded filters in the radial direction(from the outside of the filter element to the inside). As a result, theentire exterior surface of the filter is presented to the incomingcoolant fluid, not just one edge of the filter, as in most granulatedactivated carbon filters.

A particularly preferred extruded filter material is made by KXIndustries, L.P., Orange, Conn., U.S.A. Their extruded activated carbonfilter material contains one or more layers of melt-blown and spunbondedpolypropylene filter media to achieve a "graded pore density" exteriorsurface. Such filter media in addition to the extruded filter materialprovides maximum filtration while achieving the adsorptive advantages ofa particulate activated carbon filter. The outer filter component mayfilter particles from greater than 50 to about 5 microns in size.

An alternative to the use of carbon beds, one may employ a foam filterin the system for treatment of the recycled coolant. Such filters may beused to capture particulates and absorb liquid impurities, such as oil,dyes, decomposition products, and the like. A desirable foam filter is amacroreticulated foam in which the pore size is about 1 to 50 microns.Desirable foam materials are comprised of thermoset resins such aspolyurethane open cell foams and phenol-formaldehyde open cell foams.

After or prior to the carbon bed treatment, the spent coolant issubjected to filtration. The purpose of putting the filtration aftercarbon bed treatment is to use the filtration step to remove particlesof carbon that get caught up in the coolant during carbon bed treatment.If that is not a problem, then carbon bed treatment may be carried outsubsequent to one or more of the filtration steps. For example, thecarbon bed can be placed in series with the filters, such as before thefirst filter or after the first filter, but before a second filter. Inthis manner, coarse particles can be removed before the coolant ispassed to the carbon bed. This reduces the chances of rapid blockage ofthe carbon bed by large particulates. However, the carbon bed can beplaced in series after the filters. If the carbon bed is mademonolithic, as describe above, insofar that the particles of carbon arelightly interbonded by a resin without eliminating porosity of the bedto flow of coolant therethrough, then the carbon bed is preferablyplaced after the filters. In this case, the monolithic carbon particlebed serves as an effective filter of the coolant, considerable enhancingthe ultimate clarity of the processed recycled coolant.

In describing this invention, mention is made of steps of the processand features of the apparatus being in series. In doing this, it is notnecessary that such steps or features immediately follow each other. Aslong as the same fluid stream flows through the steps or features in aregular cycle of the process, then those steps and features areconsidered to be in series. However, if the fluid stream does not flowthrough the steps or features in a regular cycle of the process, thenthose steps and features are not considered to be in series.

Filtration, as noted previously, is carried out in two or more steps.This is accomplished by placing filters in series in the apparatus suchthat the spent coolant is passed in series through one filter andsubsequently, any other filter. When a monolithic extruded activatedcarbon filter is employed, a significant amount of filtration iseffected by that filter. As noted above, intervening steps in theprocess may be provided between the filters.

The filtration capabilities of these filters are based upon poreopenings which have a specific diameter. Filters having pore diametersof 25 microns or more are considered, for the purposes of the invention,to be coarse filters and filters having pore diameters of less than 25microns are considered, for the purposes of the invention, to be finefilters. Coarse filters may range in pore diameters from 25 microns toabout 200 microns, and fine filters may range in pore diameters from 0.1micron up to 25 microns. It is desirable that the first filter make acoarse separation. Typically, the first filter has about 50 micronpores. It is sometimes desirable to utilize a number of coarse filtersin series, followed by one or more fine filters in series. For example,a first filter with pores of 75 microns or less, followed by anothercoarse filter with pores of 50 microns or less, subsequently followed bya third filter with pores of 5 microns or less may prove to be asuitable filter combination. Desirable results have been obtained usinga filter sequence in which the first filter has 50 micron pores or less,followed by a fine filter that has 5 micron pores or less.

The filters suitable for this separation are typically conventionallyavailable cartridge-type filters. The filters may be made of a number ofmaterials such as rayon, rayon acetate, rayon triacetate, nylon,polyester, polypropylene, glass fiber, ceramic or metal frits, and thelike. The filters may be made of an assemblage of fibers, superimposedfabric constructions, metal or ceramic frits, and the like materials.The fabric constructions can be woven, knitted or non-woven, dependingon preference. The filters may be corrugated to increase surface areaand resin impregnation of the filter may be used to impart strength.

In specific terms, one embodiment of the process of the invention foroff-car coolant recycle is characterized as follows:

1. Cool the internal combustion engine and coolant therein.

2. Install a flushing Tee in the heater hose of the engine.

3. Pressure test the vehicle cooling system and the connected recyclingapparatus for leaks.

4. Evacuate the coolant overflow reservoir of the engine.

5. Install cross flow radiator adapter in the upper radiator hose orreplace the radiator cap with a vertical flow adaptor.

6. Pinch clamp the heater outlet hose between the heater hose Tee andthe water pump.

7. Recirculating coolant in the engine by pumping coolant from the tankin the recycler into the heater hose Tee to backflush coolant to therecycler tank. This is done for about 5 minutes, bypass filtration.

8. Remove circulation of coolant from the recycler's tank so that theflow from the engine is on the vacuum side of the pump of the recycler.This creates a closed loop system that includes the cooling system ofthe engine.

9. Aspirate SDDS into the coolant, using about 1 oz. to 1 gallon ofcoolant, corresponding to about 2-4 weight percent of SDDS basis weightof the coolant, to convert dissolved metal components into very smallparticles as noted above.

10. Then aspirate the basic coagulant into the coolant. Continue tocirculate for about 5 minutes to allow essentially complete mixing ofthe aspirated chemicals into the coolant.

11. Route the coolant through fifty and five micron filters andcirculate for about 15 minutes cycle time depending on the condition ofthe coolant.

12. A sample is taken from the sample spigot just before engaging thecarbon filter. This sample serves as a "before carbon filtration" case.

13. Route coolant through a monolithic carbon bed filter for removingoils, fine particles, excess coagulant, other organics, and circulatethe fluid for about 10 minutes The sample should be essentiallytransparent at this time.

14. Another sample is taken from the sample spigot. This sample iscompared to the sample taken in above item 13 to see if there is anychange in color. If there is no color change or lightening in the shadeof the coolant, the carbon filter may be spent. At this time the coolantshould be transparent. Take the carbon bed and the filters out of theloop before adding inhibitor.

15. Add inhibitor package to the coolant. Circulate the coolant forabout 5 minutes.

16. Check freezing point of coolant, adjust freeze point appropriatelyby adding fresh coolant through the chemical addition basin and aspirateinto the coolant. Continue addition until the desired freezing point isreached. If freezing point is above -34° F., the freezing point shouldbe lowered to -34° F. or less, as desired.

17. Turn off the recycler.

18. Crossflow adapter applications (FIGS. 1-4 reference)

a) With the machine off, close the valve on the hose connected to theradiator adapter.

b) Set valves 71 and 75 to bypass and valves 79 and 81 to drain. Checkthat the cooling system pressure is zero then remove the radiator cap.

c) Slowly turn on the pump speed regulator and evacuate the coolant inthe radiator to below the level of the upper radiator hose.

d) Remove the crossflow adapter and reinstall the upper radiator hose.

e) Set valves 71 and 75 to bypass and valves 79 and 81 to vehiclerecycle. Slowly turn on the pump speed regulator and open the valve onthe "to radiator" hose. Add enough coolant to cover the fins in theradiator. Turn off the pump speed regulator.

f) Install the radiator cap.

g) Disconnect from she heater hose tee.

h) Set valves 71 and 75 to bypass and valves 79 and 81 to vehiclerecycle. Place the hose end previously connected to the heater hose teeinto the overflow reservoir opening and open the hose valve.

i) Slowly turn on the pump speed regulator and fill the overflowreservoir to 3/4 full. Larger vehicles may require new or recycledantifreeze to be added to the overflow reservoir.

j) Turn off the pump speed regulator and cap the overflow reservoir.

19. Start Engine, run with heater on about 5 minutes, then shutdown.

20. Vertical flow adapter applications (FIGS. 1-4 reference)

a) With the machine off, close the valve on the hose connected to theradiator adapter. Remove the adapter, the coolant level should be to thetop of the radiator, and install the radiator cap.

b) Disconnect the hose attached to the heater hose tee.

c) Turn valves 71 and 75 to bypass, valves 79 and 81 to vehicle recycle,and open the valve at the end of the "to radiator" hose. Then, using thehose just disconnected from the heater hose tee, slowly add recycledcoolant to the overflow tank until it is 3/4 full. Larger coolingsystems may require additional new or recycled antifreeze to be added tothe overflow reservoir.

21. Start Engine, run with heater on about 5 minutes, then shutdown.

FIG. 1 schematically illustrates the apparatus of the invention and itsdescription characterizes the process of the invention. Apparatus 1,comprises a plurality of lines, a pump 3, a holding tank 19, filtrationcartridges 35, and an activated carbon bed cartridge 37. Each line is atubing or hose depending on location and function. Connector 59 screwson directly or indirectly (via a connecting hose of the garden hosevariety) to an engine's (101) cooling system Tee opening connection,such as 117 or 110, of Tees 127 and 114, respectively, as shown in FIG.4. For example, connector 59 can be connected directly to another hose(not shown) which in turn is directly connected to the Tee opening 117or 110. The other hose can be of the garden hose variety. Connector 67connects directly or indirectly to a vehicle's radiator, such as atradiator's 103 opening 107, or to Tee opening connection 110, in FIG. 4depending on whether a cross flow adapter or vertical flow adapter isused. Air inlet 49 is connected to an air supply source, not shown.

In pressure testing the cooling system of FIG. 4, the vacuum side topump 3, in a closed loop cycle, comprises, as shown in FIG. 3, inseries: tank 19, hose 23, through valve 81, through hose 31, throughvalve 32, through hose 15 feeds into pump 3. The pressure side comprisesfluid fed into line 7 from pump 3, to eventually pass the fluid throughconnector 59 to the vehicle's heater hose.

As shown in FIG. 3, the pressure side of pump 3, comprises line 7 totwo-way valve 71, then into line 29, to two-way valve 79. Fluid is thenpassed to line 43 through Tee 68 to connector 59, via Tee 61. Connector59 is connected to Tee opening 117 or 110, as noted above. This createsa fluid cycle involving apparatus 1 and engine 101 cooling system.

As shown, a flushing Tee 127, with opening 117 and cap 129, is providedin the heater hose of engine 101. Following, the system involvingrecycler apparatus 1 coupled to engine's 101 cooling system is pressuretested by circulating fluid into the pressure side of the recycler 1through the vacuum side, as stated above, through pump 3. Coolant iscaused to flow from pump 3 through Tee 13, line 7, through two way valve71, to Tee 73, through line 29 through two way valve 79, through line43, through Tee 68, to Tee 61 and connector 59 attached to Teeconnections 114 or 127. The preferred system uses a 30 psi systempressure gauge. Tee 61 is fitted with pressure relief valve 57 and flowfrom valve 57 goes to holding tank 19 via line 17.

In the evacuation step, with the radiator cap 106 on, which means thatthe opening at 107, FIG. 4, is covered by a standard radiator cap,overflow reservoir 105, FIG. 4, is caused to be evacuated. With theradiator cap 106 off, and connector 59 connected to Tee 127 through Teeopening 117, the cooling system of the vehicle is drained. In that case,Tee cap 129 is removed.

FIG. 4 illustrates the cooling system 101 of a typical vehicle. Thecomponents of the cooling system involve radiator 103, recovery oroverflow tank 105, radiator opening 107, radiator cap 106, upperradiator hose 109 with Tee 114 containing opening 110 and associated cap112, thermostat 111, heater control valve 113, supply heater hose 119,heater core 121, hose clamp 123, return heater hose 125, Tee 127, cap129 for Tee opening 117, return hose 128 and lower radiator hose 131.Pinch plier 130 is provided to close off flow during the process, asdesired.

Fluid circulation within cooling system 101 is shown in FIG. 4 by thearrows for back flushing out spent coolant and particulate matteraccumulated in the cooling system. The fluid is evacuated from tank 19through line 23, through three-way valve 81, through line 31, throughtwo-way valve 32, through line 15, through pump 3, through Tee 13,through line 7, through valve 71, through Tee 73, through line 29,through two-way valve 79, through line 43, through Tee 68, through Tee61, through connector 59, to Tee 127 of FIG. 4. The flushed fluid ispassed from the engine via opening 107 through connector 67, through Tee65, through check valve 66, through line 21, to tank 19.

In the recycle mode, the fluid flow on the vacuum side of the systemcomprises, in sequence, connector 67 (linked to either Tee 114 or 127 oropening 107, as the case may be), Tee 65, line 64, three-way valve 81,line 31, through two-way push button valve 32 into line 15 terminatingat pump 3. On the pressure side, fluid flows from pump 3 through Tee 13,to which is connected a Tee linked to back pressure gauge 12 via line11, and sample spigot 10 via line 9. The flow continues into line 7 totwo-way valve 71 then to line 29 into two-way valve 79, then to line 43into Tee 68, then through Tee 61 to connector 59. Fluid is passed fromthe engine via opening 107 through connector 67 through Tee 65, throughline 64, through valve 81, through line 31, through valve 32, throughline 15 to pump 3; and this recycle can include passage through thefilters and carbon bed as described below. The initial priming of pump 3involves the removal of coolant stored in tank 19 via line 23 to valve81 then to line 31, valve 32 and line 15 into pump 3. Valve 81 is turnedto initiate collection of fluid from the engine's cooling system. Airfed via line 49 passes through air regulator 51 and then into pump 3 byway of line 5.

FIG. 2 includes as part of recycler 1 addition system 2, as shown inFIG. 2A. Fluid chemical composition 88, such as SDDC, the basiccoagulant polymer, inhibitors, pH adjustment chemicals, spent and freshcoolant, or mixtures of two or more of them, can be rapidly injectedinto the spent coolant undergoing treatment thereby avoiding undesirableair introduction and assuring maximum circulation of the additives inthe spent coolant. In this embodiment, the vacuum (i.e., reducedpressure) created by the pump is the delivery means for rapidlyinjecting the additives into the spent coolant. Fluid chemicalcomposition 88 is poured from its container 87 into basin 85 containinga slanting wall funnel connected to outlet tubing 84. In thisembodiment, basin 85 contains ball 89 capable of floating on fluidchemical composition 88. The upper portion of tube 84 has a funnel shapethat decreases in diameter as the tubing recedes from its connection tobasin 85. The diameter of ball 89 is less than the opening between basin85 and tube 84, but greater than the diameter of tube 84 below theopening. The bottom of tube 84 connects with tube 83 for passage offluid chemical composition 88 through valve 32 into line 15, on thevacuum side of pump 3. Valve 32 is fitted with a push button switch thatcauses line 31 to become blocked when line 83 is opened. As a result,fluid chemical composition 88 is quickly aspirated into line 15 and intoadmixture with spent coolant in the line. This causes ball 89, floatingon the fluid chemical composition 88, to be drawn into the openingbetween basin 85 and tube 84, and to become wedged in tube 84, therebyblocking tube 84, and preventing air from entering tube 83 and recycler1.

SDDC and the basic polymer, as described above, are thus added to thespent coolant and with circulation through the system comprisingrecycler 1 and coolant system 101 without passage through the filtersand the carbon bed, they are thoroughly mixed into the spent coolant.Under these conditions, they cause isolation of metal containingparticulates that can be filtered from the coolant. Then circulatingcoolant is passed from pump 3, line 7, through valve 71, line 25 intofilter canisters 35, attached in series and connected by line 26. Thefirst canister that the fluid sees will have a coarser filter such as a50 micron filter, and the second canister will contain a fine filter,such as a 5 micron filter. The fluid recovered from the second canisterpasses by way of line 39, through valve 75, Tee 77 and line 34, Tee 73,line 29, to valve 79, into line 43 to the cooling system and circulationto the vacuum side of pump 3, as stated above. This cycle is repeatedfor the desired duration, checking samples taken from sample spigot 10for clarity, as indicated above, valve 75 is opened to cause the spentcoolant to circulate through line 27 into carbon bed cannister 37, thenout into line 41 to line 34, with the continuation of coolantcirculation as spelled out above from the pressure side of pump 3 to thevacuum side of pump 3. After the carbon bed treatment, based on thesampling via sample spigot 10, valves 71 and 75 are closed and coolantis then passed, on the pressure side, from valve 71 to line 29 to valve79. If desired, coolant can be recirculated via line 22 to tank 19 andthen circulated through line 23 to valve 81 into line 31, through valve32 into line 15 and into pump 3. An inhibitor package of chemicals, asdescribed herein, can be added to basin 85 for aspiration into thecoolant, using the procedure described above for SDDC and the basicpolymer. The freezing point of the coolant can be checked via samplingof processed coolant at sample spigot 10, and if more ethylene glycolcoolant is required, it too can be added by aspiration via basin 85.Once the desired freeze point is reached, recycler 1 can be turned offand detached from cooling system 101. The upper radiator hose 109 isreconnected to the radiator.

The pH of the ultimate recycled coolant is an important factor and a pHmeter evaluating samples taken from sample spigot 10 can be used to makethe appropriate adjustments. Chemical inhibitors and other additives canbe added to the coolant through basin 85, after the filtration andcarbon bed treatment have been completed. Typical chemicals to be addedto the refurbished coolant are Engine Coolant Treatment 2792, made byThe Penray Companies, Inc., Elk Grove Village, Ill., and a two-packageinhibitor system sold by W. R. Grace & Co., Grace Dearborn Division,Lake Zurich, Ill. Penray's Engine Coolant Treatment 2792 contains thefollowing:

    ______________________________________                                        Component         % by Weight                                                 ______________________________________                                        Sodium metasilicate                                                                              5                                                          Sodium tetraborate                                                                              15                                                          Sodium hydroxide   5                                                          Sodium nitrate     5                                                          Sodium nitrite    15                                                          2-mercaptobenzothiazole                                                                         --                                                          Sodium tolyltriazole                                                                            --                                                          ______________________________________                                    

The Grace Dearborn inhibitor package contains two additives. The firstadditive is designated as Dearborn CW-1606. It comprises about 15 weight% potassium hydroxide, 2 weight % sodium silicate and 2 weight %potassium nitrate. The other part of the Dearborn package is DearbornCW-1607 and it contains phosphoric acid. Additive CW-1606 is added firstand thoroughly mixed in the coolant before adding CW-1607. About fourfluid ounces of each of them is added for every gallon of the coolant.

The Penray inhibitor is a one part inhibitor. If this inhibitor is used,3 ounces per gallon of cooling system volume is added to basin 85.

The Grace Dearborn inhibitor is a two-part inhibitor. If this inhibitoris used, 4 ounces of the first part (Part 3) per gallon of coolingsystem volume, is added.

EXAMPLE

The entire sample for this experiment comprised approximately 14 gallonsof recycled, inhibited coolant prepared by recycling three (3) 5.33gallon batches of used coolant.

1. Recycling chemical preparation- Preparation of enough precipitant andcoagulant to recycle one 5.33 gallon batch of used spent alkalinecoolant in the coolant recycler such as illustrated in FIG. 1.

a. Precipitant--12.6 ml. of undiluted Rochester Midland (Rochester,N.Y.) Midfloc 1300L (SDDC) was added to 145 ml of distilled water.

b. Coagulant--78.8 ml. of ethylene glycol and 16.1 ml of 10.2 volumepercent, anion-exchange resin (Rohm & Haas Amberlyst A27) treatedRochester Midland (Rochester, N.Y.) Midfloc 1320L (polyquaternary aminesold by Rochester Midland) was added to 62.7 ml. of distilled water.

(1) The 10.2 volume percent, anion-exchange resin treated RochesterMidland Midfloc 1320L was produced by taking undiluted Rochester MidlandMidfloc 1320L, diluting it with distilled water so that itsconcentration was 10.2 volume percent and then passing it through anionexchange resin to remove chloride ions and replace them with hydroxideions.

2. Recycling--The equipment was a prototype of that described in FIG. 1with the filter chambers having pressure gauges upstream and down streamof each filter chamber in addition to the two pressure gauges on therecycler control panel. There was a rotometer-style flow meter upstreamand downstream of the filter chambers. The first filter chamber housed a20 inch, nominal 50 micron retention Hytrex cartridge filter. The secondfilter chamber housed a 20 inch, nominal 5 micron retention Hytrexcartridge filter. The third filter chamber housed a 20 inch AmetekRFC-20 carbon cartridge. This carbon filter could be bypassed ifdesired.

3. Recycling process

a. The recycler's tank was filled with 5.33 gallons of a used coolant.The 55 gallon drum which contained approximately 45 gallons of usedcoolant was agitated using an air diaphragm pump similar to the pumpused in the recycler. The used coolant was pumped from the bottom of the55 gallon drum and returned to the drum. A tee and section of tubingwith a valve at the end of the tubing in the pump discharge line wasused to fill a 3000 ml. pitcher. The pitcher was dumped into a 5 gallonbucket. The bucket was poured into the recycler tank. A total of 5.33gallons were poured into the recycler tank.

b. Recycling

(1) The recycler's pump was started with the used coolant passing fromthe tank through the pump, through the 50 and the 5 micron particlefilters and back to the tank. The flow rate was approximately 2 gallonsper minute.

(2) Then 157.6 ml. of the precipitant was poured into the recycler tankfollowed by 157.6 ml. of the coagulant approximately a minute or twolater.

(3) The coolant circulated for approximately 15 to 20 minutes.

(4) The carbon filter which had been bypassed was now engaged.

(5) Coolant circulated for approximately 10 to 15 more minutes.

(6) The recycled, uninhibited coolant was pumped into a 5 gallon pail.

(7) Approximately 5 samples were taken during the recycling operation tomonitor progress.

(8) This operation was repeated for the other two 5.33 gallon batches ofused coolant.

c. Blending and inhibiting

(1) 12.5 gallons of product from the three recycler operations wereplaced in a 14 gallon tank for blending.

(2) 3930 ml. of distilled water was added to raise the freeze point fromapproximately -51° F. to -39° F.

(3) Added to the diluted coolant product as described above, withthorough mixing, was four fluid ounces for every gallon of the coolantof Grace Dearborn inhibitor CW1878 which comprises 0.0045 vol. fractionof Belclene 200 (Aqueous solution of poly(maleic acid) [homopolymer of2-butenedioic acid], now sold by FMC Corporation, Process AdditiveDivision, 1735 Market St., Philadelphia, Pa. 19103) and 0.9955 vol.fraction of CW-1606. Then four fluid ounces for every gallon of thecoolant of Grace Dearborn inhibitor of CW-1879 (same as CW-1607) wasthoroughly mixed in the treated diluted coolant.

Analytical evaluation of the treated coolant is set forth in thefollowing table. The results of the analytical evaluation are comparedto current ASTM standards and a current General Motors ("GM") standardfor concentrates.

    __________________________________________________________________________                      REQUIRED SPECIFICATIONS                                                       D3306                                                                         ASTM NEW   GM 1825M GM NEW                                  ASTM              Concentrate                                                                              Concentrate (as of                               TEST DESCRIPTION  4/16/91    09/17/92)   Example                              __________________________________________________________________________    D 1122 Specific gravity                                                                         1.110 to 1.145                                                                           1.11 to 1.14                                                                              1.09                                 D 1177 Freezing point, 50% dilute                                                               -34° F./-37° C. max                                                        -34° F./-37° C.                                                             -42.6° C.                     D 1120 Boilint point: Concentrate                                                               325° F./183° C. max                                                        300° F./149° C.                                                             --                                   50% dilute        226° F./107.8° C. min                                                      --          107.8° C.                     D 1882 Effect on automotive finish                                                              No effect  No effect   No effect                            D 1119 Ash content (mass %)                                                                      5 max     5 max       1.4                                  D 1287 pH, 50% vol distilled water                                                              7.5 to 11.0                                                                              7 to 11     9.6                                  D 3634 Chloride (ppm)                                                                           25 max     --          45.2                                 D 1123 Water (mass %)                                                                            5 max     5 max       46.5                                 D 1121 Reserve alkalinity                                                                       Report     10 min      11.1                                 D 3306 notes: Color                                                                             Distinictive                                                                             Distinct green                                                                            Green                                Effects on non metals                                                                           No adverse None on hoses,                                                                            No effect                                              effect     gaskets, coatings                                Storage stability --         Slight cloudiness                                                                         Clear, no ppt. -                                                  and ppt.    PASS-                                D 1384-Corrosion in glassware, weight loss (mg)                               Copper            10 max     20 max      3                                    Solder            30 max     20 max      3                                    Brass             10 max     10 max      1                                    Steel             10 max     10 max      1                                    Cast Iron         10 max     10 max      2                                    Aluminum          30 max     20 max      0                                    D 2570-Simulated service, weight loss (mg)                                    Copper            20 max     20 max      10                                   Solder            60 max     40 max      2                                    Brass             20 max     20 max      17                                   Steel             20 max     20 max      2                                    Cast Iron         20 max     20 max      2                                    Aluminum          60 max     40 max      0                                    Reserve alkalinity % change after                                                               --         25 max      2.2                                  D2570                                                                         D4340-Corrosion of cast aluminum                                                                1.0 max    1.0 max     0.28                                 alloys at heat rejecting sur-                                                 faces (mg/cm2/wk)                                                             D 1881 Foaming: Volume (ml)                                                                     150 max    50 max      25                                   Break time (sec)  5 max      5 max       1.2                                  D 2809 Cavitation-Erosion                                                                       8 min      8 min       8*                                   Pitting           8 min      --          --                                   Appearance                   --          44% Green                            CONSTITUENTS                                                                  Ethylene Glycol (wt. %)                                                                         --         85 min      54                                   Other Glycols (wt. %)                                                                           --         10 max      --                                   Total dissolved solids after filtration                                                         --         --          14000                                Heavy metals (ppm)                                                            Fe                --         --          <0.1                                 Cu                --         --          <0.1                                 Zn                --         --          --                                   Al                --         --          <0.5                                 Pb                --         --          <0.2                                 Glycol degrade products (mg/l)                                                Glycolate/Formate --         --          7100                                 Nitrite Nitrogen (NO2)                                                                          --         No addition 52 (None added)                      Chloride (Cl)     --         No limit    59                                   Sulphate (SO4)    --         --          340                                  __________________________________________________________________________     Legends: CONCENTRATE  New undiluted antifreeze.                               PREDILUTE  Recycled antifreeze before diluting 50% with water.                *Rerun through a 5 micron filter                                         

An advantage of the use of a basic coagulating agent is that it will notintroduce chloride into the treatment of the spent alkaline coolant.Chloride, as note above, deleteriously attacks the protective oxidelayer of the engine block, and therefore it is desirable to avoid itspresence. In addition the polyquaternary coagulating agents describedpossess the capability of sequestering and tying up chloride, and tosome extent, the basic coagulating agent of the invention acts like ananion exchange resin, serving to reduce the presence of strongly acidicanions, such as chloride, in the coolant, thus returning less of theanions to the engine on recycling.

We claim:
 1. A process for the treatment and recovery of spent alkalinecoolant from an internal combustion engine comprising the followingsteps:a) feeding sodium dialkyldithiocarbamate into spent alkalinecoolant removed from the engine to cause dissolved metals therein toform insoluble particles; b) treating the spent coolant of step a) witha basic coagulating agent comprising a quaternary ammonium polymercontaining hydroxide ions that at least partially replace acid ions insaid polymer; c) filtering the spent coolant through two or morefiltration steps and d) passing the spent coolant through a bed ofcarbon particles, to provide a cleaner liquid; and e) adding to thecleaner liquid a combination of corrosion inhibitors, buffering agentsand alkali, whereby the treated coolant has a pH between about 8 andabout 11, and can be recycled to the engine for effective coolantperformance therein.
 2. The process of claim 1 wherein the filtrationsteps comprise two filtration cannisters in series, one which contains acoarse filter, the other of which contains a fine filter.
 3. The processof claim 2 wherein the bed of carbon particles comprises a singlecannister containing a bed of activated carbon particles.
 4. The processof claim 1 wherein the quaternary ammonium groups are located in thebackbone of the polymer.
 5. The process of claim 1 wherein thequaternary ammonium groups are located on moieties that are pendant fromthe backbone of the polymer.
 6. The process of claim 1 wherein the alkylgroup of the sodium dialkyldithiocarbamate is a lower alkyl.
 7. Theprocess of claim 6 wherein the lower alkyl contains 1 to 4 carbon atoms.8. The process of claim 7 wherein the alkyl is methyl and the sodiumdialkyldithiocarbamate is sodium dimethyldithiocarbamate.
 9. The processof claim 1 wherein the spent coolant is directly taken from the enginefor treatment in step a) and coolant from the process is recycled to thesame engine.
 10. The process of claim 1 wherein the spent coolant iscollected in bulk, processed, and then recycled to another engine. 11.The process of claim 4 wherein the polymer is a condensation product ofepichlorohydrin and alkyl amine, which is treated to remove chlorinetherefrom.
 12. The process of claim 4 wherein the polymer is acondensation product of ethylene dichloride and alkyl amine, which istreated to remove chlorine therefrom.
 13. The process of claim 11wherein the alkyl amine is dimethylamine.
 14. The process of claim 1wherein feeding and treating of steps a) and b), respectively, are byaspiration.
 15. The process of claim 1 wherein the combination ofcorrosion inhibitors, buffering agents and alkali is fed to the coolantby aspiration.